Lecture 1

Question 0

Why is there considerable genetic variation in any population?

Answer 0

Variation is due to mutations (changes in the genotype)

Could be tiny change in DNA or large change in chromosomes

Question 1

What is it known as when parents pass on a mixture of the characteristics they received?

Answer 1

Recombination

Question 2

What is the difference between the genotype and phenotype?

Answer 2

Genotype - genetic makeup of a cell, organism or individual (I.e. The specific allele makeup of the individual)
Phenotype - the sum of all physical and biochemical characteristics

Question 3

What is genetics?

Answer 3

The study of the flow of biological information from one generation to the next

Question 4

Define the following; gene, allele, homozygous, heterozygous, P, F1

Answer 4

Gene - unit of inheritance
Allele - each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome
Homozygous - both copies of allele at the same time
Heterozygous - copies of alleles are different
P - parental
F1 - first filial generation (directly after parents)

Question 5

What is Mendels first law?

Answer 5

The law of segregation

Question 6

What is a Monohybrid cross?

Answer 6

Mating individuals that differ in only one characteristic

Question 7

What characteristics did Mendel look at in pea plants?

Answer 7

Seed shape
Seed colour
Plant height
Pod shape
Pod arrangement
Pod colour
Flower colour

Question 8

Which part of the plant contains pollen and which part contains ovules?

Answer 8

Stamen contains pollen

Ovary contains ovules

Question 9

Why is Mendels first law called the law of segregation?

Answer 9

Individuals carry 2 copies of each gene but only pass 1 of the 2 to any one offspring ie. The two alleles segregate in the gametes

Question 10

If both gametes are heterozygous Yy what would the offsprings genes look like?

Answer 10

YY -1/4
Yy - 1/2
yy - 1/4
1:2:1
Y is dominant so is likely to be shown in 3/4 offspring

Question 11

What does the dominant allele do to the recessive allele?

Answer 11

Nothing - the dominant allele codes for something with an activity while the recessive codes for something with no activity

Question 12

Which allele is most likely to be passed on to offspring?

Answer 12

Neither, they have an equal chance although dominant is more likely to be expressed

Question 13

When can a recessive allele be expressed?

Answer 13

Homozygous (aa)
Sex linked genes
Imprinted genes